A known technique of organizing information for communication to selective call radios such as pagers in a radio communication system is to arrange the addresses of selective call radios for which message information is included in a predetermined portion of a transmission cycle, such as a frame, at the beginning of the predetermined portion of the transmission cycle in an address field, separated from the message information intended for the selective call radios. This has the advantage of improving the battery life of the selective call radios, because a radio which has no information in the predetermined portion of the transmission cycle can quickly revert to a low power mode as soon as it determines its address is not in the address field.
When the addresses are positioned at the beginning of the predetermined portion of the transmission cycle, the position of the message information intended for the selective call radios must be determined by the selective call radios in order for them to recover the message information. A technique for determining the position of the information is used in the well known FLEX.TM. protocol of Motorola, Inc. of Schaumburg, Ill. In this protocol a starting position of message information within the predetermined portion of the transmission cycle is indicated by a vector which has a length and position determined on a one for one basis by the length and position of the address associated with the vector. While this protocol works quite well, it has limitations. One limitation is that, as channel arrangements have become more sophisticated, the amount of information required in a vector requires a longer vector than the associated address. Another limitation is that the message information must be within the same predetermined portion of the transmission cycle. This other limitation arises partly from the limitation on the length of the vectors due to their correspondence to the length of the addresses in the FLEX.TM. protocol.
Thus, what is needed is an improved technique for organizing message information in a radio communication system.